Thomas f



(No Model.)

T. P. MoOOY. KNIFE FOR PAPER CUTTING MACHINES.

No. 596,530. Patented Jan. 4,1898.

UNITED STATES PATENT OFFICE.

THOMAS FQMCGOY, OF NEW YORK, N. Y.

KNIFE FOR PAPER-CUTTING MACHINES.

SPECIFICATION forming part of Letters Patent. No. 596,530, dated January 4, 18985 Application filed May a, 1897. Serial no. 635,119. "(No model.)

' To all whom it may concern:

Be it known that I, THOMAS F. MCCOY, of NewYork city, county and State of New York, have invented an Improved Knife for Paper- Cutting Machines, of which the following is a specification. c

This invention'relates to an improvement in knives for paper-cutting machines, and

. has for its object to provide means for ren- 1'0 dering knives again serviceable after being worn. These knives have'a limited vertical adjustment along the knife-bars, and after the cutting edge has been worn substantially to the length of this adjustment the knives r 5 were heretofore rendered useless. I propose to provide the knife when worn with an additional back, which permits its further adjustment and thereby greatly increases the length of its life.

In the accompanying drawings, Figure 1 is a face view, partly in section, of my improved knife; Fig. 2, a cross-section thereof, showing it attached to the knife-bar; Fig. 3, a crosssection on line 3 3, Fig. 1; Fig. 4, a face view ofa modification of the knife Fig. 5, a crosssection on line 5 5, Fig. 4; Fig. 6, a face view of a further modification of the knife; and Fig. 7, a cross-section on line 7 7, Fig. 6.

' The letter a represents the usual wroughtiron body or blade of a knife for paper-cutting machines, being a long fiat bar having a beveled edge, to the back of which the steel cutting edge b is welded. The blade a is provided at suitable intervals with transverse 5 perforations (1., adapted for the reception of fastening-screws 0, having nuts 0, and by which the knife is attached to the knife-bar d. This knife-bar is provided with an ofiset d above the blade and with set-screws 6, pass- 40 ing through the offset, by meansof which the blade is rendered vertically adjustable to a limited extent. The fastening-screws 0 pass through upright slots (1 of the knife-bar, so

that such screws may follow the adjustment of the blade. To lower the blade, the nuts 0' are loosened, the screws 6 turned down, and

the nuts 0 again tightened up. When the screws 0 have reached the lower extremities of slots (1 further adjustment of the knife ceases, and knives worn to require further lowering were rendered useless.

In order to permit the knives when so worn to be again rendered useful, I attach to the upper or blunt edge a a back f, which is a long narrow strip of metal of the same thickness as the thickness of the blade; The back f is preferably secured to the blade by means of the keys,plugs,or dovetail wedges g. (Illustrated in Figs. 1 and 3.) Here the blade 0. and back f are provided at their contiguous edges with dovetail recesses opening into one another and adapted for the reception of the keys or plugs. These keys are'preferably cast into the recesses, and when set will efiectivelyv connect the parts. To procure a better finish, it is desirable that the front and back of the keys be countersunk, as illustrated in Fig. 3.

I prefer to arrange number of dowel-pins 71., that pass longitudinally through back f and into the upper or blunt edge of the blade a. As the knives in 'paper-cuttin g machines have a slanting downward motion, it is of importance that the connection between back and knife be such as to efiectively resist the shearing strain thereby produced. This result is accomplished to a satisfactory extent by the combined use of the keys g and dowel-pins h, the keys efiecting a firm connection,while the dowel-pins serve to assist in taking up the shearing strain.

between the keys 9 a The back f should be provided with perforations f in alinementwith the perforations a, the distance between the perforations f and upper edge of back f being preferably equal to the distance between perforations a and back a After the back has been fitted to the knife the screws 0 are again turned up, so that the back rests against the offset (1!, Fig. 2, and in this way the knife may be used up to an additional length equal to the height of the back. Thus the life of the knife is prolonged to a considerable extent, and the steel cutting edge I) may be used 'up to near itsup per terminal. j

In Figs. 4 and 5 the connecting-keys are made in the form of centrally-contracted elliptical plugs i in lieu of being made of the angular form shown in Figs. 1 to 3. I

In Figs. 6 and 7 the wedge-shaped keys are replaced by screws It, that pass longitudinally through the'back and engage tapped openings in the blade.

\ -What I claimis 1. Aknifefor paper-cutting macl1ines,c0m- 3. Aknife for paper-cuttinginachincs,c0mposed of a perforated blade, abackperforated posed of a recessed blade, a recessed back, in alinement With the blade, and means for connecting-plugs engaging the same, and connecting the back with the blunt edge of dowel-pins that pass longitudinally through 5 the blade, substantially as specified. the back and into the blunt edge of the blade, I 5

2. Aknife for paper-cutting machines,c0msubstantially as specified. posed of a recessed blade, a recessed back, THOMAS F. MCCOY. and wedge-shaped plugs that engage the re- Witnesses: cesses and connect said back to the blunt edge WILLIAM SCHULZ,

.10 of the blade, substantially as specified. F. V. BRIESEN. 

